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NORMAL BRAIN TISSUE RESPONSE TO PHOTODYNAMIC THERAPY: HISTOLOGY, VASCULAR PERMEABILITY AND SPECIFIC GRAVITY
Author(s) -
Dereski M. O.,
Chopp M.,
Chen Q.,
Hetzel F. W.
Publication year - 1989
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1989.tb04322.x
Subject(s) - evans blue , photodynamic therapy , histopathology , extravasation , edema , vascular permeability , pathology , medicine , permeability (electromagnetism) , lesion , histology , nuclear medicine , chemistry , biochemistry , organic chemistry , membrane
— The response of photodynamic therapy on normal brain was investigated in 140 Fisher rats. The rats were injected i.p. with Photofrin II (12.5mg/kg) and 48 h later the dural area over the frontal cortex was photoactivated with red light (630 ± 1 nm) from an argon dye laser. Treatment was performed with optical energy densities of 140 and 70 J/cm 2 . Histopathology, vascular permeability and specific gravity measurements were conducted on different populations of rats at 4 h, 24 h, 72 h and 1 week after photodynamic therapy (PDT). Histopathology revealed similar gross and microscopic pathology associated with light energies of 70 and 140 J/cm 2 after all time points. A large cerebral infarct approximately the size of the brain surface area treated, evolved 24 h following treatment. Evans blue extravasation indicated a small area of vascular permeability evident as early as 4 h following PDT treatment at both energy levels, with increasing permeability evident at later time points. Specific gravity measurements taken on a representative area of the lesion indicated a significant (P < 0.01) amount of edema present at 24 h post treatment with a gradual reduction approaching control values over the time period of] week. The data indicate a significant amount of damage to normal brain from low PDT treatment doses.